1. Field of the Invention
The present invention relates to a rotary piston internal combustion engine of trochoidal type of construction, of which the housing or casing consists of side parts and at least one shell, casing or mantle part having respectively a dual-arc or curved inner surface or mantle runway. The housing has an shaft with at least one eccentric per inner surface or mantle runway journalled to pass through the housing. A triangular piston means having corners thereof in sliding engagement along the pertaining inner surface or mantle runway is journalled upon a roller bearing as to the eccentric. The triangular piston means rotates as controlled or regulated by a synchronous gear transmission arranged between a side wall of one of the side parts and the eccentric.
2. Description of the Prior Art
A piston of such an engine provided for higher loading is cooled conventionally with oil which enters via axial and radial bores in the shaft and the eccentric into the bearing space and transmission space and drains into an oil sump. Under these circumstances the oil must be kept away from the working chambers of the engine via oil inner seals located in the side walls of the piston. Because of the space requirement thereof, constructive difficulties resulted to accommodate and install such seals, and additionally, it is hardly possible, with such oil seals to preclude completely the passage of the oil into the working chambers or spaces and to prevent a worsening of the exhaust gas or discharge values of the engine as caused by such oil seal problems.
German Offenlegungsschrift 35 45 818 and a corresponding U.S. Pat. No. 4,801,254-Eiermann dated Jan. 31, 1989 belonging to the assignee of the present invention and based thereon describes an engine of the aforementioned type having roller bearings between the piston and eccentric with which the lubrication can be limited or restricted to a minimum quantity or volume of oil of which excesses now only need to be adequate or sufficient for lubrication of the synchronization gear transmission and the sealing elements of the piston. Special oil inner seals in the piston side walls can be eliminated accordingly.
According to the disclosure of German Patent 35 45 818 and U.S. Pat. No. 4,801,254-Eiermann correspondingly there was proposed to supply the oil tot he eccentric bearing from outside to a side of the synchronous gear transmission. With certain types of construction, however, this is not possible and consequently the oil or lubricant must be supplied from the other side of the eccentric remote or away from the transmission.